Mexico's state oil company says that searchers have recovered four more bodies from a petrochemical plant wrecked by a huge explosion on the country's Gulf coast, raising the death toll to 32.

Petroleos Mexicanos said in a statement Sunday that rescuers with dogs had reached some of the area's most affected by Wednesday's blast and had located more bodies. It said all the workers in the plant that day have been located.

The company said more than 130 people in all suffered injuries when the explosion rocked the plant in Coatzacoalcos, 600 kilometers (370 miles) southeast of Mexico City.

Pemex has said the explosion happened after a leak but has not determined the source.

The Clorados 3 plant of Petroquimica Mexicana de Vinilo produces the hazardous industrial chemical vinyl chloride.